红外光学系统系列化方案

分析了红外光学系统品种随意发展带来的问题,研究提出了专用组件系列化发展的技术途径。选择适合的系列化的数学方法,分析了红外光学系统的应用特性及系列化的条件,研究提出了红外光学系统系列化的方案和型谱架构。     

Tracing of interference fringes using average gray value and simultaneous row and column scan

An algorithm for computer tracing of interference fringes is reported. The method uses the average gray-level value for thresholding, row and column scans for determining the type of the scan and simultaneous row and column scan for tracing. The proposed method yield good result even for low-contrast and high-noise images. The program for the interferogram tracing was written using MATLAB6.     

Bulk modulus and its pressure derivatives of cuprous halides

The ab initio pseudopotential approach to the total crystal energy is presented using local DF formalism. The expressions for bulk modulus, its first and second pressure derivatives for group I-VII semiconductor binary compounds are derived. The expression for the second pressure derivative of the bulk modulus for four-fold crystal structures is derived for the first time within the pseudopotential framework. The computed results of the bulk modulus for cuprous halides are very close to the available experimental data.     

The experimental investigation of a glow discharge in a toroidal tube

A glow discharge in a toroidal tube with axial discharge current is investigated. The investigation was carried out for a discharge as a whole, not for electrodal zones and the positive column separately. The volt-ampere characteristics for different pressures and Paschen's curves for different gases were measured. The curves obtained are compared with analogous ones for a cylindrical tube. The conditions for the existence of a glow discharge in a toroidal tube and the processes passing there are discussed on the basis of the measured curves. The experiments were carried out in air, helium, argon and neon.     

Long range elastic interaction of prismatic dislocation loop with a grain boundary

The expressions for the displacement and the stress field around a prismatic infinitesimal dislocation loop lying near the welded boundary and for the displacement field near the slipping boundary are given. The expression for the total force by which the loop is either attracted or repelled from the grain boundary (welded or slipping) was calculated. The forces are graphically illustrated for different combinations of material constants. The calculations were carried out within the isotropic elasticity.The author is indebted to Dr. F. Kroupa for valuable discussion.     

New hyperbolic models of dusty gas flow

The paper presents hyperbolic models for dusty gas flow formulated for single- and multivelocity approximations with account for inter-fractional heat transfer. Characteristic analysis of equations for the model was performed. The Godunov method and linearized Riemann solver was applied for a solution on curvilinear mesh: the Prandtl?Meyer problem for air-droplet mixture was solved. The simulation results were compared with the self-similar solution.     

Nuclear Level Density with Non-zero Angular Momentum

The statistical properties of interacting fermions have been studied for various angular momentum with the inclusion of pairing interaction. The dependence of the critical temperature on angular momentum for several nuclei,have been studied. The yrast energy as a function of angular momentum for 28 Si and 24Mg nuclei have been calculated up to 60.0 MeV of excitation energy. The computed limiting angular momenta are compared with the experimental results for 26Al produced by 12C 14N reaction. The relevant nuclear level densities for non-zero angular momentum have been computed for 44Ti and l36Ba nuclei. The results are compared with their corresponding values obtained from the approximateformulas.     

Optimum Design for RF Windows in Millimeter Wave High Power Tubes

The pill-box and block RF windows for millimeter wave (MMW) tubes are presented. The pill-box window is suitable for broadband MMW tubes. And the block window can be used for high power tubes in short MMW. The equivalent circuits for two windows are given. To reach better match characteristics in wider operating bandwidth, the optimum design methods for pill-box and block window in MMW tubes are described in this paper. The testing results show that the theoretic computation is fast and useful accuracy. The design methods possess references value to designer for MMW tubes.     

粉末压片法波长色散X射线荧光光谱分析铁矿石样品的矿物效应校正初探

利用10个国内铁矿石标样,对粉末压片法波长色散X射线荧光光谱分析铁矿石样品中主、次量元素时的矿物效应校正进行了初步探讨。文章采用两种方法试图降低由于矿物效应带来的影响。第一种方法(角度校正法)是在测量每个样品 前(包括校正标样以及未知样),对每个待测元素的2θ角度进行实际测量,以校正可能存在的角度偏移;第二种方法(峰面积法)是用峰面积代替峰强度,以校正由于峰形变化所带来的影响。最后用回归分析后的Ｋ因子进行比较。结果表明, 两种方法对矿物效应进行校正都可以不同程度地改善铁矿石中主要元素的校正曲线,尤其是S的校正曲线改善明显。如果在角度校正法或峰面积法的基础上再用基体校正系数,除总Fe外,其他组分均可以满足分析要求,但总Fe仍需要采取 其他措施。     

High-speed mathematical models of cogeneration steam turbines: Optimization of operation at heat and power plants

The approach was developed for creation of high-speed mathematical models of cogeneration turbines; these models are the tools for fast optimization of operation modes of large-scale cogeneration heating plants. The approach was developed for identification of mathematical models of steam turbines via measuring its parameters. The example of parameters identification is presented for steam turbine T-100/120–130. The optimization computations of operation modes for a cogeneration heating plant were the basic ones for plotting equivalent energy characteristics at a given consumer heat load.     

Electronic Stopping Power for 0.05--10MeV Protons in a Group of Organic Materials

Electronic stopping powers for 0. 05-10 MeV protons in a group of organic materials are systematically calculated. The calculations are based on Ashley＇s dielectric model, and an evaluation approach of optical energy loss function is incorporated into Ashley＇s model because no experimental optical data are available for most of the organic materials under consideration. The Barkas-effect correction and Bloch correction are included. The proton stopping powers for the considered organic materials except for mylar in the energy range from 0.05 to 10 MeV are presented for the first time. The results may be useful for studies of various radiation effects in these materials and for space research.     

Preparation of calibrating standards for x‐ray fluorescence spectrometry of trace metals in plastics

Convenient x‐ray fluorescent spectrometry was developed for the determination of V, Cr, Co, Ni, Ge and Sb in plastic materials. The calibrating standards were prepared by casting of polyurethane or polyester including a xylene solution of organometallic compounds as a standard. The calibrating disk had a homogeneous elemental distribution and excellent durability. The calibration curves of six elements showed a good linearity of less than 50 mass ppm for V and Ni, 100 mass ppm for Co and Ge, 200 mass ppm for Cr, and 400 mass ppm for Sb. The lower limits of detection (3σ) of the present method were 0.19 mass ppm for V, 0.42 for Cr, 0.24 for Co, 0.18 for Ni, 0.066 for Ge, and 2.1 for Sb. The proposed method has been applied to several different industrial plastics. The quantitative results are in good agreement with those obtained by the AAS method and x‐ray fluorescent spectrometry using the fundamental parameter calculation method. Copyright © 2003 John Wiley & Sons, Ltd.     

ICP-MS测定碳酸锂中微量元素

用ICP-MS测定碳酸锂中微量杂质元素的基本条件,确定了合适的样品处理、分解方法,研究了元素间的干扰.方法检出限K0.020μg/g,Na o.025μg/g,Ca0.009μg/g,Mg 0.010μg/g,SO2-4 0.050μg/g;加标回收率在94.0%-102.0%,测定精密度RSD 0.5%-2.1%,方...     

Probability representation of the quantum evolution and energy-level equations for optical tomograms

The von Neumann evolution equation for the density matrix and the Moyal equation for the Wigner function are mapped onto the evolution equation for the optical tomogram of the quantum state. The connection with the known evolution equation for the symplectic tomogram of the quantum state is clarified. The stationary states corresponding to quantum energy levels are associated with the probability representation of the von Neumann and Moyal equations written for optical tomograms. The classical Liouville equation for optical tomogram is obtained. An example of the parametric oscillator is considered in detail.     

Scattering matrix for Raman effect in cubic crystals

The scattering matrix for Raman effect in cubic crystals for any general orientation of the crystal and any angle of scattering is given. The averages of the matrix over all possible orientations is also given and checks with the well known value of 6/7 for the depolarisation of degenerate lines for transverse scattering. The scattering matrix for backward scattering in terms of polar angles and for some special cases are also given.     

Helium-3 adsorption refrigerator cooled with a closed-cycle cryocooler

A helium-3 adsorption refrigerator cooled with a pulse-tube cryocooler is developed. The refrigerator has two stages of adsorption pumping. The first stage is designed for the condensing and pumping of helium-4, whose cooling capacity is used for the condensation of helium-3. The second stage is designed for pumping helium-3. The final temperature reached by the refrigerator is 0.305 K. This temperature is retained for at least 24 h. The time required for helium recondensation and the obtainment of low temperature is 1.5 h. The cryostat is a self-contained instrument, as it contains no external gas-supply pipelines and the working gas is stored directly within the working volume of the refrigerator. The work is performed in the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research.     

Waveguide discrete modes in slab and cylindrical FIR laser

The characteristic equation is solved for oversized slab and cylindrical hollow waveguides. The outter medium is a dielectric or a metal for cylindrical waveguides, and a dielectric for slab waveguides. The results are applied to consider the resonance conditions for a FIR laser cavity.     

Scattering of evanescent electromagnetic waves by a cylinder near the flat boundary: the Green function and fast numerical method

The scattering of plane evanescent waves by a cylinder is studied. The Green function for the Helmholtz equation for two dielectrics with flat interface is found and applied for the numerical calculation of the scattered field by the boundary elements method. The Green function keeps close track of scattering, including multiple reflections. The result may be applicable for the data analysis in near-field optical microscopy.     

Relations among temporal acuity, hearing loss, and the perception of speech distorted by noise and reverberation

Eight normal listeners and eight listeners with sensorineural hearing losses were compared on a gap-detection task and on a speech perception task. The minimum detectable gap (71% correct) was determined as a function of noise level, and a time constant was computed from these data for each listener. The time constants of the hearing-impaired listeners were significantly longer than those of the normal listeners. The speech consisted of sentences that were mixed with two levels of noise and subjected to two kinds of reverberation (real or simulated). The speech thresholds (minimum signal-to-noise ratio for 50% correct) were significantly higher for the hearing-impaired listeners than for the normal listeners for both kinds of reverberation. The longer reverberation times produced significantly higher thresholds than the shorter times. The time constant was significantly correlated with all the speech threshold measures (r = -0.58 to -0.74) and a measure of hearing threshold loss also correlated significantly with all the speech thresholds (r = 0.53 to 0.95). A principal components analysis yielded two factors that accounted for the intercorrelations. The factor loadings for the time constant were similar to those on the speech thresholds for real reverberation and the loadings for hearing loss were similar to those of the thresholds for simulated reverberation.     

Nuclear Level Density with Non-zero Angular Momentum

The statistical properties of interacting fermions have been studied for various angular momentum with the inclusion of pairing interaction. The dependence of the critical temperature on angular momentum for several nuclei, have been studied. The yrast energy as a function of angular momentum for 28Si and 24 Mg nuclei have been calculated up to 60.0 MeV of excitation energy. The computed limiting angular momenta are compared with the experimental results for ^26Al produced by ^12C＋ 14N reaction. The relevant nuclear level densities for non-zero angular momentum have been computed for ^44Ti and ^136 Ba nuclei. The results are compared with their corresponding values obtained from the approximate formulas.